GALLERY: The 10 Coolest Skyscrapers in the United States

HVAC engineers and architects may not always see eye-to-eye when it comes to designing in enough room for HVAC systems, but you have to admit that the architects can come up with some pretty striking designs from time to time. Here are the 10 coolest skyscrapers in the United States, as selected by HPAC Engineering Senior Editor Ron Rajecki.